Comparisons, boolean logic, and conditions

What you will build

Derive not started, learning, or completed from progress.

Understand the idea first

Derive not started, learning, or completed from progress.

Build it step by step

function progressLabel(done, total) {
  if (done <= 0) return '未开始';
  if (done >= total) return '已完成';
  return `学习中：${done}/${total}`;
}
console.log(progressLabel(3, 12));

1. Open the project from the previous lesson and record its current result.
2. Type and run the example, then complete this task: Predict and test negative, zero, middle, exact-total, and over-total values.
3. Change at least one input, predict the result, and verify it.
4. Create and repair this lesson's typical failure: Do not confuse assignment with comparison; use strict equality and define boundaries.

Read the important lines

• Derive not started, learning, or completed from progress.
• Read the code as input, processing, and output; point to each part.
• A first successful run is not enough; verify a different input and an edge case.

Common mistakes and what to check

Practice without copying

Predict and test negative, zero, middle, exact-total, and over-total values.

Completion check

• I produced the required visible result
• I can explain the input, processing, and output
• I tested normal, edge, and failure cases